Ultralight motors?

I'm looking for a 35-50 hp 2 stroke suitable for a legal 103.7
ultralight. Anybody here know of a Rotax 477 or 503 - or a suitable
substitute that is not being used by some other fool?


Now I know that "friends don't let friends fly 2 strokes", but with
the (bleepin') catch-22 in the spot pilot rules, that about all that's
left to me.

Richard

Hows about a 1/2 VW? I think Len Milholland's 1/2 does about 30-35 HP.
Not sure what the finished weight is though...

Scott


Richard Lamb wrote:
I'm looking for a 35-50 hp 2 stroke suitable for a legal 103.7
ultralight. Anybody here know of a Rotax 477 or 503 - or a suitable
substitute that is not being used by some other fool?


Now I know that "friends don't let friends fly 2 strokes", but with
the (bleepin') catch-22 in the spot pilot rules, that about all that's
left to me.

Richard

I'm not sure if the weihgt is similar, but Hummel also makes a 1/2 VW
engine but in all of their planes it puts it over US ultralight
weights. IIRC (and I might not), the difference between the equivalent
2-stroke Rotax was around 25 pounds. If you start out with a light
enough design to begin with it might make it.

One major plus with the 1/2 VW is the fuel consumption. From what I've
heard it's down around 1.3GPH. That's some pretty cheap flying .

Weight is always an issue. But it's not the only one.

Leonard's approach keeps the block intact (not cut in half), so it
will be a little heavier than needed. It is sturdier, tho.

The real down side to ANY 1/2 VW setup is the vibration.
It's a low frequency - high amplitude shake that is not ok on an
extremely light airframe.

I also have doubts about the 30-35 HP specification.
VW engines are fin area limited. While they can make the claimed
power - for a short time - once the heat limit is reached, the power
MUST be reduced to avoid overheating and failures.
I'd believe 20 to MAYBE 25 hp continuous.

Lastly, there he RPM issue. In order to make power, the engine
has to be spun up. That requires a VERY short propeller, and
LESS than 50% prop effeciency.

My most recent parasol (I hate to say my LAST parasol, but...)
has a Great Plains 2180 VW on it. It also has a 60 inch long
Tennessee Props propeller. The long prop limits max rpm to
less than 3000 static. That's well below the RPM needed for max
HP, but it's still high enough on the torque curev to pull ok.

The long prop increases prop effeceincy to the point that overall
performance is actually quite good.

With all the accessories, that engine weighs in ar 208 lbs (!).

So, all things considered, I think a two-stroke would be the proper
choice for a true ultralight.

254 pounds is a damned difficult limit.


Richard

(Pardon, please, my spelling errors. Posting via Yahoo has it's
limits too)

("Richard Lamb" wrote)
[snips]
Weight is always an issue. But it's not the only one.

I also have doubts about the 30-35 HP specification.
VW engines are fin area limited. While they can make the claimed
power - for a short time - once the heat limit is reached, the power
MUST be reduced to avoid overheating and failures.
I'd believe 20 to MAYBE 25 hp continuous.

So, all things considered, I think a two-stroke would be the proper
choice for a true ultralight.

254 pounds is a damned difficult limit.


http://www.aero-works.net/store/detail.aspx?ID=87
Horsepower 16.5 HP, Weight 7.85 lbs., Length 7.3 inches, Width 12.5 inches,
Propeller sizes 28 x 10, 32 x 12 ........$1,495.95

Two of these gives you 33 hp at 16 lbs.

What the heck ...a Tri-Motor. 50 hp for 24 lbs. g

Original CriCri had two 9 hp engines and it still managed 100+ mph.

http://www.flight.cz/cricri/english/...escription.php
"Nowadays, builders are using engines Valmet, JPX, Limbach, 3W, Rotax,
Zenoah, Hirth, and I am glad to see, that are recommended also Czech ZDZ
Model."

(For people [like me] who enjoy Googling for more information - engines)


Montblack
CriCri list at Yahoo

Montblack wrote:


http://www.aero-works.net/store/detail.aspx?ID=87
Horsepower 16.5 HP, Weight 7.85 lbs., Length 7.3 inches, Width 12.5 inches,
Propeller sizes 28 x 10, 32 x 12 ........$1,495.95


What's the TBO on that engine, one hour or two?

--

FF

wrote:

Montblack wrote:


http://www.aero-works.net/store/detail.aspx?ID=87
Horsepower 16.5 HP, Weight 7.85 lbs., Length 7.3 inches, Width 12.5 inches,
Propeller sizes 28 x 10, 32 x 12 ........$1,495.95



What's the TBO on that engine, one hour or two?

If you care for it properly and run it often instead of letting it
sit for long periods, then it should exceed TBO

wrote

What's the TBO on that engine, one hour or two?

I have seen little engines of that type that are surprisedly well built.
Details such as roller bearing on the crankshaft, and needle bearings on the
rod large end. Nickel coated iron sleeve, and ringed piston. They will run
many hours without attention, if kept cool and well lubricated.

The biggest issue I see with those engines is the fact that it is not a
mixture controllable carb. I suppose you could rig up something to adjust
the needle settings.

How about a 1 person B-17? Or a lay down B-29, with the pilot looking out
the nose?

Oh, I've got it! A B-36! Add some of those model jet engines! 6 turnin'
and 4 burnin'!

BFG
--
Jim in NC

Richard Riley wrote:
On 16 Oct 2005 14:08:00 -0700, "Richard Lamb"
wrote:

:I'm looking for a 35-50 hp 2 stroke suitable for a legal 103.7
:ultralight. Anybody here know of a Rotax 477 or 503 - or a suitable
:substitute that is not being used by some other fool?

Take a look at these, especially the weight...

http://www.zanzotteraengines.com/498ai.htm

http://www.ultralightnews.com/sunfun2001/zanzottera.htm

Zonzonetta says they are buidling for the UAV market, it is
far from clear that they would knowingly sell for a manned
aircraft.

That said, has anyone ever seen price information for one of these?

--

FF

No pricing shown on their web page.
And the gearbox info was a little thin.
But that 498 does look like a potential winner.



Richard